[Haskell-cafe] Seven ways to store 16 bytes

[Felipe Lessa]

On Tue, Jan 05, 2010 at 04:06:09PM -0800, Mark Lentczner wrote:
> In preparing the speed ups in uuid-0.1.2, I investigated
> various ways to store 16 bytes of data in a Haskell object.
> Surprisingly, storing as 4 Word32 values in a standard data
> type worked best for that application.

However, on an Core 2 Duo in x86-64 mode with GHC 6.10, 2 Word64
values wins over 4 Word32 values.  Attached is the modified
source code.  Here is the summary between them

  equal-itself/words                  76.41 ns
  equal-itself/words64                64.52 ns

  equal-same/words                    79.64 ns
  equal-same/words64                  67.85 ns

  equal-differ/words                  66.11 ns
  equal-differ/words64                62.79 ns

  compare-same/words                  80.59 ns
  compare-same/words64                68.68 ns

  compare-differ/words                67.14 ns
  compare-differ/words64              64.22 ns

  toList-and-sum/words               991.32 ns
  toList-and-sum/words64             839.45 ns

  map-and-sum/words                    1.04 us
  map-and-sum/words64                  1.12 us

  fold-and-sum/words                 882.88 ns
  fold-and-sum/words64               755.98 ns

  fromList-and-eq/words              740.41 ns
  fromList-and-eq/words64            749.07 ns

  build-and-eq/words                 484.54 ns
  build-and-eq/words64               447.81 ns

  unfold-and-eq/words                577.12 ns
  unfold-and-eq/words64              541.46 ns

Cheers,

--
Felipe.
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